VK, Youtube, Steam, Discord.
VK got pretty much any movie, anime, music, whatever. And OK got stuff, that got banned even on VK btw lol. No idea, what do ppl do on facebook. Well, it's great for finding photos and places linked to 'em, if that's so important for ya. I usually watch anime and listen to music on VK.
Youtube is abit of a drug, but some vids should be watched there, not on VK.
Steam seems to be losing ground fast, but it's much more developed than other gaming platforms still.
I almost never use discord tbh, coz if I want to chat, telegram is usually enough. A mite of a Durov fan, I guess :d